112 THE DEVONIAN OF MISSOURI. 



Superfamily Nuculacea 



Family Nuculidae 

 Genus Nucula Lamarck 



Nucula cf. lirata (Conrad) 



Plate 25, figures 13 and 14 



1842. Nuculites lirata Conrad, Jour. Acad. Nat. Sci., Phila., vol. VIII, p. 250, pi. XV, 



fig. 7. 

 1870. Nucula lirata Hall, Prelim. Notice Lamellibranchiata, 2, p. 3. 

 1885. Nucula lirata Hall, Pal. N. Y., vol. V, pt. I, Lamellibranchiata II, p. 316, pi. 



XLV, figs. 5, 11, 15, 17-22, 24, 25; pi. XCIII, fig. 5. 

 1903. Nucula lirata Clarke, N. Y. State Mus. Bull. 65, p. 462. 



1909. Nucula lirata Grabau and Shimer, N. Am.- Index Fossils, vol. I, p. 395, fig. 503d. 

 1913. Nucula lirata Prosser and Kindle, Maryland Geol. Surv., Middle and Upper 

 Devonian, pp. 229-30, pi. 25, figs. 6-8 and 9, 10 (?). 

 Description — "Shell of medium size, ovate-triangular; length from one-third to one- 

 fourth greater than the height; basal margin regularly curving, more abruptly rounded 

 at the posterior extremity; cardinal margin slightiy arcuate, gradually sloping toward 

 the posterior; anterior end short, subtruncate, usually abruptly rounded. Valves very 

 gibbous, ventricose in the umbonal region; beaks, at the anterior third or fourth of the 

 length of the shell, distant, elevated, rising considerably above the hinge-line; umbo 

 very prominent. Test thick, marked by regular, strong, subangular concentric undula- 

 tions, which are crossed by extremely fine radiating striae." Hall, 1885. 



Remarks — One internal mould from the top of the Snyder Creek shale agrees with 

 N. lirata in shape and muscular impressions. The dentition is not preserved. It is 

 much smaller than ordinary specimens of N. lirata. No exteriors have been collected. 

 The identification is uncertain at the best. 



Occurrence — Snyder Creek shale, Cow Creek, Callaway County. 



Nucula snyderensis n. sp. 

 Plate 25, figures 17 and 18 



Description — Shell small, ovate; length about one-third greater than breadth; 

 basal margin regularly curving, more abruptly rounded at posterior and anterior ex- 

 tremities. Cardinal margin nearly straight, sloping gently toward the posterior; anterior 

 end short, symmetrically rounded; part behind beaks about twice as long as in front. 

 Valves thin; beaks only slightly elevated. Muscular scars small, deep; palial line dis- 

 tinct. 



All of the specimens in the collections are internal moulds, and the surface markings 

 are not preserved. The dentition is not preserved. 



The specimens differ from those identified as Nucula lirata (Conrad) in being much 

 longer compared to the height, much less ventricose, and beaks less prominent. 



Occurrence — Snyder Creek shale, Cow Creek, Callaway County. 



Superfamily Pteriacea 



Family Conocardiidae 



Genus Conocardium Bronn 



Conocardium ohioense Meek 



Plate 26, figures 1-7 



1873. Conocardium Ohioense Meek, Geol. Surv. Ohio, I, pt. II, Paleontology, pp. 



203-206, pi. 18, fig. 9. 

 1885. Conocardium Ohioense Hall, Pal. N. Y., V, pt. I, Lamellibranchiata II, p. 411, 

 pi. 68, figs. 2-3. 



